Tue·Jan 28, 2020Tuesday·January 28, 2020

1. 01*

   Neutron Induced Fission Fragment Angular Distributions, Anisotropy, and Linear Momentum Transfer Measured with the NIFFTE Fission Time Projection Chamber

   D. Hensle🇺🇸 · J.T. Barker · J.S. Barrett🇺🇸 · N.S. Bowden🇺🇸 · K.J. Brewster · J. Bundgaard🇺🇸 · Z.Q. Case · R.J. Casperson🇺🇸 · D.A. Cebra🇺🇸 · T. Classen🇺🇸 · D.L. Duke🇺🇸 · N. Fotiadis and 37 other authors

   The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration has performed measurements with a fission time projection chamber (fissionTPC) to study the fission process by reconstructing full three-dimensional tracks of fission fragments and other ionizing radiation. The amount of linear momentum imparted to the fissioning nucleus by the incident neutron can be inferred by measuring the opening angle between the fission fragments. Using this measured linear momentum, fission fragment angular distributions can be converted to the center-of-mass frame for anisotropy measurements. Angular anisotropy is an important experimental observable for understanding the quantum mechanical state of the fissioning nucleus and vital to determining detection efficiency for cross section measurements. Neutron linear momentum transfer to fissioning ${}^{235}$U, ${}^{238}$U, and ${}^{239}$Pu and fission fragment angular anisotropy of ${}^{235}$U and ${}^{238}$U as a function of neutron energies in the range 130 keV--250 MeV are presented.

   nucl-exPRC(2020)·14 citations
2. 02*

   Search for jet quenching effects in high multiplicity pp collisions at $\sqrt{\mathrm{s}}$=13 TeV

   P.M. Jacobs (for the ALICE Collaboration)🇺🇸

   The ALICE Collaboration reports a search for jet quenching effects in pp collisions at $\sqrt{\mathrm{s}}$=13 TeV, in events selected on high multiplicity compared to the minimum bias population. The measurement is based on the semi-inclusive acoplanarity distribution of jets recoiling from a high-$p_{\mathrm{T}}$ trigger hadron. Significant broadening of the recoil jet acoplanarity distribution is observed in high multiplicity pp collisions, in both data and in simulations based on the PYTHIA model. Analysis is ongoing to elucidate the origin of this effect.

   nucl-exhep-exNPA(2021)·7 citations
3. 03*

   Measuring nuclear reaction cross sections to extract information on neutrinoless double beta decay

   M. Cavallaro🇮🇹 · F. Cappuzzello🇮🇹 · C. Agodi🇮🇹 · L. Acosta🇲🇽 · N. Auerbach🇮🇱 · J. Bellone🇮🇹 · R. Bijker🇲🇽 · D. Bonanno🇮🇹 · D. Bongiovanni🇮🇹 · T. Borello-Lewin🇧🇷 · I. Boztosun🇹🇷 · V. Branchina🇮🇹 and 63 other authors

   Neutrinoless double beta decay (0v\b{eta}\b{eta}) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own anti-particles (Majorana particles). Presently, this physics case is one of the most important research "beyond Standard Model" and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the 0v\b{eta}\b{eta} decay process involves nuclei, its analysis necessarily implies nuclear structure issues. In the NURE project, supported by a Starting Grant of the European Research Council (ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extract information on the 0v\b{eta}\b{eta} Nuclear Matrix Elements. In DCE reactions and \b{eta}\b{eta} decay indeed the initial and final nuclear states are the same and the transition operators have similar structure. Thus the measurement of the DCE absolute cross-sections can give crucial information on \b{eta}\b{eta} matrix elements. In a wider view, the NUMEN international collaboration plans a major upgrade of the INFN-LNS facilities in the next years in order to increase the experimental production of nuclei of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest as candidates for 0v\b{eta}\b{eta}.

   nucl-exJ.Phys.Conf.Ser.(2018)·1 citation
4. 04*

   NURE: an ERC project to 'measure' the nuclear matrix elements

   M. Cavallaro🇮🇹

   The NURE (NUclear REactions for neutrinoless double beta decay) project has been selected for receiving funding in the call Starting Grant 2016 of European Research Council (ERC). The project, which takes advantage of nuclear physics methods to give a contribution to the neutrino physics, has a duration of 5 years. A key aspect is the use of the K800 Superconducting Cyclotron, for the acceleration of the required high resolution and low emittance heavy-ion beams, and of the MAGNEX large acceptance magnetic spectrometer, for the measurement of the reaction cross sections. These facilities are in operation at INFN Laboratory Nazionali del Sud in Catania (Italy).

   nucl-exPoS(2018)·3 citations
5. 05*

   Nuclear structure studies performed using the (18O,16O) twoneutron transfer reactions

   D. Carbone🇮🇹 · C. Agodi🇮🇹 · F. Cappuzzello🇮🇹 · M. Cavallaro🇮🇹 · J. L. Ferreira🇧🇷 · A. Foti🇮🇹 · A. Gargano🇮🇹 · S.M. Lenzi🇮🇹 · R. Linares · J. Lubian🇧🇷 · G. Santagati🇮🇹

   Excitation energy spectra and absolute cross section angular distributions were measured for the 13C(18O,16O)15C two-neutron transfer reaction at 84 MeV incident energy. This reaction selectively populates two-neutron configurations in the states of the residual nucleus. Exact finite-range coupled reaction channel calculations are used to analyse the data. Two approaches are discussed: the extreme cluster and the newly introduced microscopic cluster. The latter makes use of spectroscopic amplitudes in the centre of mass reference frame, derived from shell-model calculations using the Moshinsky transformation brackets. The results describe well the experimental cross section and highlight cluster configurations in the involved wave functions.

   nucl-exnucl-thJ.Phys.Conf.Ser.(2018)·0 citations
6. 06*

   Charge-state distributions of 20Ne ions emerging from thin foils

   M. Cavallaro🇮🇹 · G. Santagati🇮🇹 · F. Cappuzzello🇮🇹 · D. Carbone🇮🇹 · R. Linares · D. Torresi🇮🇹 · L. Acosta🇲🇽 · C. Agodi🇮🇹 · D. Bonanno🇮🇹 · D. Bongiovanni🇮🇹 · T. Borello-Lewin🇧🇷 · I. Boztosun🇹🇷 and 33 other authors

   New experimental measurements of charge state distributions produced by a 20Ne10+ beam at 15 MeV/u colliding on various thin solid targets are presented. The use of the MAGNEX magnetic spectrometer enabled measurements of the 8+ charge state down to fractions of a few 10-5. The use of different post-stripper foils located downstream of the main target is explored, showing that low Z materials are particularly effective to shift the charge state distributions towards fully stripped conditions. The dependence on the foil thickness is also studied and discussed.

   nucl-exResults Phys.(2019)·25 citations
7. 07*

   Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive ${}^{222}$Ra and ${}^{228}$Ra Beams

   P.A. Butler🇬🇧 · L.P. Gaffney🇬🇧 · P. Spagnoletti🇬🇧 · K. Abrahams🇿🇦 · M. Bowry🇨🇦 · J. Cederkäll🇸🇪 · G. De Angelis🇮🇹 · H. De Witte🇧🇪 · P.E. Garrett🇨🇦 · A. Goldkuhle🇩🇪 · C. Henrich🇩🇪 · A. Illana🇮🇹 and 31 other authors

   There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in ${}^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing ${}^{222}$Ra as pear-shaped with stable octupole deformation, while ${}^{228}$Ra behaves like an octupole vibrator.

   nucl-exhep-phnucl-thphysics.atom-phPRL(2020)·96 citations
8. 08*

   Search for muon catalyzed $d^{3}He$ fusion

   V.D. Fotev (1) · V.A. Ganzha (1) · K. A. Ivshin (1) · P.V. Kravchenko (1) · P.A. Kravtsov (1) · E.M.Maev (1) · A.V. Nadtochy (1) · A.N. Solovev (1) · I.N. Solovyev (1) · A.A. Vasilyev (1) · A.A.Vorobyov (1) · N.I. Voropaev (1) and 12 other authors

   This report presents the results of an experiment aimed at observation of the muon catalyzed ${}^{3}Hed$ fusion reaction ${}^{3}He+\mu d{\to }^{3}He\mu d{\to }^{4}He(3.66MeV)+p(14.64MeV)+\mu$ which might occur after a negative muon stop in the $D_2{+}^{3}He$ gas mixture. The basic element of the experimental setup is a Time Projection Chamber (TPC) which can detect the incoming muons and the products of the fusion reaction. The TPC operated with the $D_2{+}^3\tilde{H}e(5$ gas mixture at $31K$ temperature. About $10^8$ ${}^{3}He\mu d$ molecules were produced with only 2 registered candidates for the muon catalyzed ${}^{3}Hed$ fusion with the expected background $N_{bg}=2.2\pm 0.3$ events. This gives an upper limit for the probability of the fusion decay of the ${}^{3}He\mu d$ molecule $P_F{(}^{3}He\mu d)\le 1.1\cdot 10^{-7}$ at 90% C.L. Also presented are the measured formation rate of the ${}^{3}He\mu d$ molecule ${\lambda }_{d3He}=192(3)\cdot 10^6{s}^{-1}$ and the probability of the fast muon transfer from the excited to the ground state of the $\mu d$ atom $q_{1S}=0.80(3)$.

   nucl-exPhys.Part.Nucl.(2024)·0 citations
9. 09*

   NURE: An ERC project to study nuclear reactions for neutrinoless double beta decay

   M. Cavallaro · E. Aciksoz · L. Acosta · C. Agodi · N. Auerbach · J. Bellone · R. Bijker · S. Bianco · D. Bonanno · D. Bongiovanni · T. Borello · I. Boztosun and 62 other authors

   Neutrinoless double beta decay (0{\nu}\b{eta}\b{eta}) is considered the best potential resource to determine the absolute neutrino mass scale. Moreover, if observed, it will signal that the total lepton number is not conserved and neutrinos are their own anti-particles. Presently, this physics case is one of the most important research beyond Standard Model and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the \b{eta}\b{eta} decay process involves nuclei, its analysis necessarily implies nuclear structure issues. The 0{\nu}\b{eta}\b{eta} decay rate can be expressed as a product of independent factors: the phase-space factors, the nuclear matrix elements (NME) and a function of the masses of the neutrino species. Thus the knowledge of the NME can give information on the neutrino mass scale, if the 0{\nu}\b{eta}\b{eta} decay rate is measured. In the NURE project, supported by a Starting Grant of the European Research Council, nuclear reactions of double charge-exchange (DCE) will be used as a tool to extract information on the \b{eta}\b{eta} NME. In DCE reactions and \b{eta}\b{eta} decay, the initial and final nuclear states are the same and the transition operators have similar structure. Thus the measurement of the DCE absolute crosssections can give crucial information on \b{eta}\b{eta} matrix elements.

   nucl-exPoS(2017)·34 citations
10. 10*

    Impact of ionizing radiation on superconducting qubit coherence

    Antti Vepsäläinen🇺🇸 · Amir H. Karamlou🇺🇸 · John L. Orrell🇺🇸 · Akshunna S. Dogra🇺🇸 · Ben Loer🇺🇸 · Francisca Vasconcelos🇺🇸 · David K. Kim🇺🇸 · Alexander J. Melville🇺🇸 · Bethany M. Niedzielski🇺🇸 · Jonilyn L. Yoder🇺🇸 · Simon Gustavsson🇺🇸 · Joseph A. Formaggio🇺🇸 · Brent A. VanDevender🇺🇸 · William D. Oliver🇺🇸

    The practical viability of any qubit technology stands on long coherence times and high-fidelity operations, with the superconducting qubit modality being a leading example. However, superconducting qubit coherence is impacted by broken Cooper pairs, referred to as quasiparticles, with a density that is empirically observed to be orders of magnitude greater than the value predicted for thermal equilibrium by the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. Previous work has shown that infrared photons significantly increase the quasiparticle density, yet even in the best isolated systems, it still remains higher than expected, suggesting that another generation mechanism exists. In this Letter, we provide evidence that ionizing radiation from environmental radioactive materials and cosmic rays contributes to this observed difference, leading to an elevated quasiparticle density that would ultimately limit superconducting qubits of the type measured here to coherence times in the millisecond regime. We further demonstrate that introducing radiation shielding reduces the flux of ionizing radiation and positively correlates with increased coherence time. Albeit a small effect for today's qubits, reducing or otherwise mitigating the impact of ionizing radiation will be critical for realizing fault-tolerant superconducting quantum computers.

    ↳ quant-phnucl-exphysics.ins-detNature(2020)·254 citations
11. 11*

    Bulk properties and multi-particle correlations in large and small systems

    Bjoern Schenke🇺🇸 · Chun Shen🇺🇸 · Prithwish Tribedy🇺🇸

    Charged particle production is calculated in a hybrid framework consisting of the IP-Glasma initial state, MUSIC viscous relativistic fluid dynamics, and the UrQMD microscopic hadronic cascade. Using one set of parameters, we compute observables for a large variety of collision systems. We compare to experimental data in p+p, p+Pb, Xe+Xe, Au+Au and Pb+Pb collisions at various energies, and make predictions for potential O+O runs at RHIC and LHC.

    ↳ nucl-thhep-phnucl-exNPA(2021)·10 citations
12. 12*

    Centrality criteria of inelastic nucleon-nucleon collisions

    Vladimir Komarov🇷🇺 · Bota Baimurzinova🇷🇺 · Ainur Kunsafina🇷🇺 · Dmitry Tsirkov🇷🇺

    A process of inelastic nucleon-nucleon collisions with the impact parameter less than a radius of the nucleon quark core is considered. The criteria for selection of such collisions from a full array of the nucleon-nucleon interactions are suggested.

    ↳ hep-phnucl-exnucl-th1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.